That’s incredible. I happen to use a Logitech thumb-ball mouse, so I’m quite familiar with the concept. Never thought to use a conventional mouse upside down though; that’s incredibly resourceful.

I don’t know if you or anyone else here needs to see this, but this reminds me of Ben Heckendorn who makes custom accessibility controlers. He’s also known for a bunch of stuff, including Bill Paxton Pinball, the Hand-held 2600, podcasts, YT videos, and more junk on his site.